The objective of orthodontic treatment is to reconfigure teeth in a patient's mouth to achieve a comfortable, functional bite and a more attractive smile. Orthodontists use various hardware configurations commonly known as braces to achieve this. Braces primarily consist of brackets, archwires, and auxiliaries, e.g., elastics, springs, stops and tiebacks. Together, brackets, archwires, and auxiliaries enable the orthodontist to tailor movement and repositioning of individual or segments of teeth by transferring forces to the dental facial structures.
Orthodontists have used stops on archwires since the beginning of orthodontics as a specialty in the early twentieth century. A traditional use of a stop is to prevent the archwire from sliding through a bracket beyond the desired position. This situation would cause discomfort to the patient because the end of the wire would poke out beyond the bracket into the cheek. Stops had the appearance of a V-Shaped dimple and were bent in the archwire by the orthodontist. The placement of two such stops on either side of an orthodontic bracket would prevent the archwire from sliding through the brackets and thus prevent irritation of the oral soft tissues. Two stops could also be placed on the distal side of the terminal bracket on each side of a segment of teeth to prevent space from opening in that segment, for example distal to the right and left maxillary lateral incisor brackets.
Tie backs were also bent in the archwire and were a modification of a stop. A conventional tie back loop is shown in FIG. 1. A conventional tie back loop 1 bent in archwire 2 has, as shown in FIG. 1, the appearance of a tear drop and is usually placed mesial to the first molar brackets. The tie back loop 1 can be tied to the bracket 3 (to a hook 3′ of the bracket) with a ligature 4 for the purpose of preventing space from opening throughout the dental arch. Tie back loops could also be placed several millimeters mesial to the first molar brackets in an archwire which also had closing loops bent in it. The tie backs could then be tied to the first molar bracket with a ligature and thereby activate the closing loops.
It is also possible to provide a tie back hook on an archwire, e.g., by soldering. A conventional tie back hook 5 is shown in FIG. 2 fixed to the archwire 2. The tie back hook 5 can be tied to the bracket 3 (to a hook 3′ of the bracket) with a ligature 4 for the purpose of preventing space from opening throughout the dental arch.
The bending of stops and tie backs in an archwire is a time consuming process. The development of crimpable stops facilitated the placement of stops. An archwire could be marked with a wax marker and a small stainless steel tube could be slid on the wire to the mark and simply crimped with an orthodontic plier to secure it in place. The placement of crimpable stops serves the same functions of preventing archwires from sliding through the brackets and preventing space from opening in a segment as the stops bent in the archwire did. Conventional crimpable stops cannot be used as tie backs, however, since there is no way to tie a ligature to them.
A crimpable stop having a hook is also known. See U.S. Pat. No. 5,306,142 to Richards, the contents of which are incorporated herein by reference. The Richards patent discloses an orthodontic device defining an anchor for an elastic, ligature or spring. It combines a ball hook attached to a crimpable stop, the stop having a tubular body with inner wire-engaging surfaces coated with an abrasive material to produce an anti-sliding and anti-rotating engagement with the wire when crimped down upon the wire. This patent discloses that the crimpable ball hooks can be mounted on archwires and when used with intermaxillary elastics can provide intermaxillary fixation, can be mounted on a lip bumper received in buccal tubes or can be mounted on the inner bow of a face bow received in buccal tubes. The hooks tend to be large, e.g., have a height of about 4 mm in the gingival-occlusal direction and can cause irritation of the gingiva.